The RNA annealing mechanism of the HIV-1 Tat peptide: conversion of the RNA into an annealing-competent conformation
The RNA annealing mechanism of the HIV-1 Tat peptide: conversion of the RNA into an annealing-competent conformation
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DOI：
10.1093/nar/gkq1339
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发表时间：
2011-05-01
影响因子：
14.9
通讯作者：
Schroeder, Renee
中科院分区：
文献类型：
--
作者：
Doetsch, Martina;Fuertig, Boris;Schroeder, Renee
核酸与（部分）互补的 RNA 或 DNA 链的退火涉及重要的细胞过程。多种蛋白质已被证明可以加速 RNA/RNA 退火，但它们的作用方式仍然主要不确定。为了研究蛋白质促进退火加速的机制，我们选择了一种短肽HIV-1 Tat(44-61)，它可以有效地加速反应。肽的活性受到单价和二价阳离子的强烈调节，这暗示了 RNA 和肽之间静电相互作用的重要性。肽的诱变说明了带正电荷的氨基酸在 RNA 退火中的主导作用——分子的总电荷和肽内碱性氨基酸的精确分布都很重要。此外，我们发现 Tat(44-61) 通过熵项而不是焓项驱动 RNA 退火反应。一维 NMR 数据表明，该肽改变了可能的 RNA 结构的群体分布，以有利于易于退火的 RNA 构象，从而增加了成功退火的碰撞 RNA 分子的比例。
The annealing of nucleic acids to (partly) complementary RNA or DNA strands is involved in important cellular processes. A variety of proteins have been shown to accelerate RNA/RNA annealing but their mode of action is still mainly uncertain. In order to study the mechanism of protein-facilitated acceleration of annealing we selected a short peptide, HIV-1 Tat(44-61), which accelerates the reaction efficiently. The activity of the peptide is strongly regulated by mono- and divalent cations which hints at the importance of electrostatic interactions between RNA and peptide. Mutagenesis of the peptide illustrated the dominant role of positively charged amino acids in RNA annealing-both the overall charge of the molecule and a precise distribution of basic amino acids within the peptide are important. Additionally, we found that Tat(44-61) drives the RNA annealing reaction via entropic rather than enthalpic terms. One-dimensional-NMR data suggest that the peptide changes the population distribution of possible RNA structures to favor an annealing-prone RNA conformation, thereby increasing the fraction of colliding RNA molecules that successfully anneal.